The present invention relates to continuous casting for the manufacture of multilayer components whereby molten metal, for example molten steel, is in some fashion combined with sheet stock.
Multilayer integral or laminated components can presently be made only through rolling, welding or mold casting on a discontinuous basis. The welding or rolling methods are disadvantaged by the fact that the individual layers of the compound component are inadequately bonded together whereby a bond is to be understood only in a sense of a homogenic material texture sufficient to be able to take up different types of loads without delamination. Usually deficiencies along that line show up already for example during further working such as deforming or forming the component to obtain a reduced wall thickness.
Presently however desired compound components of the multilayer variety are of increasing interest particularly for example in the case of pipes of relatively large diameter. It is known for example through publication in VDI Nachrichten (VDI news) No. 23, page 8 of June 10, 1983 to provide multi-layer compounds in a particular manner, using a pilot process for making a natural gas pipeline in a multilayer compound fashion. It was found that just an increase in pipe diameter is not a technical economical feature just for increasing the flow cross-section so as to increase the throughput of such pipes. Increasing pipes above the presently deemed optimum pipe diameter of 1420 mm appears to be impractical as per the present time. Throughput is increased for example by increasing the pumping pressure up to 100 or 120 bars. For these pipes a well thickness of 35 mm are required.
During cooling of continuously cast metal such as steel it has become known through a handbook by Erhard Hermann, 1958 (Handbuch des Stranggiessen, Seite 153) to introduce compact material for example in the form of a rolling rod made of the same steel. This rod does not have to melt completely but becomes an integral part of the casting. This particular method, however, is limited to the concept of supplementing the cooling in the interior of the casting head under utilization of the solid rod being introduced and having the same composition. Therefore this particular method does not produce a multilayer component in which the different layers have different properties. Moreover the resulting product is not comparable with the product envisioned in the present invention.